Electrical adapter for medical diagnostic instruments using leds as illumination sources

ABSTRACT

An adapter for permitting a medical diagnostic instrument having an illumination source including at least one LED (light emitting diode) to be used with a power supply normally configured for use with a diagnostic instrument having at least one incandescent lamp as an illumination source. The adapter includes circuitry for compensating LED specific characteristics for permitting the power supply to be used with the LED.

FIELD OF THE INVENTION

[0001] The following application generally relates to the field ofillumination, and more particularly to an LED illumination systemintended for use with hand held medical diagnostic instruments, such asthose used in a physician's or health care provider's office, or othermedical environments.

BACKGROUND OF THE INVENTION

[0002] Many manufacturers of hand-held medical diagnostic instrumentproducts including otoscopes, ophthalmoscopes, et al., such as thosefrom Heine Inc., Welch Allyn, Inc., and Keeler Instruments, amongothers, have long since utilized miniature incandescent lamps, such ashalogen and xenon lamps, as illumination sources. These lamps aretypically provided within the handle or the head of the instrument andutilize fiber optic bundles or other optical means to transmit the lightfrom the miniature lamp to the tip opening of the diagnostic instrument,such as an ophthalmoscope, otoscope, or similar device.

[0003] Power sources for these lamps are typically either wall mountedor are portable, in the form of batteries provided in the instrumenthandle and having a nominal voltage of approximately 2.5 or 3.5 volts.These voltages are convenient values, since they match both a stackedarrangement of two or three Nickel cadmium batteries and 3.5 volts inparticular is favored since it is also the voltage of a single lithiumion cell. Examples of instruments having same are described, forexample, in U.S. Pat. Nos. 4,012,686, 5,559,422, 5,177,424, and5,542,904.

[0004] More recently, there has been considerable interest in the fieldin light emitting diodes (LEDs) as a potential substitute for miniatureincandescent lamps. White versions of these LEDs, such as thosedescribed, for example, in U.S. Pat. Nos. 6,069,440 and 5,998,925, amongothers, the entire contents of which are herein incorporated byreference, provide better illumination capability than predecessor LEDsand are therefore coveted for a myriad of applications due to theirlonger life, resistance to shock and impact loads, cooler operatingtemperatures and alternative spectral content as compared with the aforementioned miniature incandescent lamps. Moreover and adding LEDs ingeneral, such as color LEDs, provide additional benefits such asspectral tuning, IR, spectrally specific illumination, and the like.

[0005] It is a general desire in the field that future productimprovements incorporating white LEDs as illumination sources becompatible with both the mechanical and electrical features of existingpower supplies to which these instruments are interconnected. There are,however, a number of significant differences which must be recognized inthe incorporation of the above illumination devices into any previouslyknown medical diagnostic instrument. For example, white LEDs, such asthose described above, experience a large variation in forward voltageas compared with miniature incandescent lamps, as well as significantdifferences in current versus light output and color characteristics.There are also mechanical issues relating to the incorporation of anyadapter into a medical diagnostic instrument.

[0006] In summary, there is a need to develop an adaptive means whichcan be mechanically, optically and electrically incorporated into thedesign of a hand-held medical diagnostic instrument so as to permit aninstrument having LEDs as an illumination source to be readily used witha variety of existing power supplies and charging apparatus. There is anadditional need to enable current instrument heads which formerly usedminiature incandescent lamps to utilize white or color LEDs with theseexisting power sources.

SUMMARY OF THE INVENTION

[0007] It is therefore a primary object of the present invention toovercome the above-noted deficiencies of the prior art.

[0008] It is another primary object of the present invention to developelectrical adapters that can permit LEDs, such as white LEDs, to beutilized in existing known hand-held medical diagnostic instrumentswithout requiring major configuration changes to already existing powersupplies and/or electrical charging apparatus.

[0009] It is yet another primary object of the present invention toprovide an electrical adapter which permits white LEDs to be utilized inalready existing hand-held diagnostic instruments, such as otoscopes,without significantly impacting the mechanical and/or optical functionor design of the instruments.

[0010] Therefore and according to a preferred aspect of the invention,there is provided an electrical adapter for use with a medicaldiagnostic instrument typically configured with an incandescent lamp asan illumination source and a power supply for powering said incandescentlamp, said adapter having means for permitting at least one LED to beused as the illumination source for said instrument while permittingsaid existing power supply to used therewith.

[0011] Preferably, means are included for compensating LED-specificcharacteristics for permitting the power supply to be used with themedical diagnostic instrument. The adapter preferably includes an AC toDC converter in order to compensate for variations in forward voltage ofat least one white LED used as an illumination source and to effectpolarity discrepancies. The AC to DC converter can consist of, forexample, at least one diode bridge or a MOSFET switch. The adapter alsopreferably includes means for compensating LED specific differences suchas current, voltage boost, regulation, and color sense, therebypermitting use of the diagnostic instrument having at least one whiteLED with already existing power supplies and/or battery chargingapparatus.

[0012] According to one preferred embodiment, the LED electrical adaptercan be disposed within the head of the diagnostic instrument so as topermit interchangeability of illumination devices; that is, in which oneinterchangeable instrument head can include a miniature incandescentlamp and another interchangeable head includes a least one white LED andan electrical adapter permitting the LED to be utilized with theremainder of the instrument whether the instrument includes a wallmounted power supply or batteries.

[0013] Alternatively and according to yet another preferred embodiment,the LED electrical adapter can be fitted in lieu of a conventionalbattery within the instrument handle. The adapter, in fact, can bemanufactured and sized so as to effectively replace a battery within thehandle.

[0014] According to yet another preferred aspect of the invention, thereis provided in combination, an adapter for use with a medical diagnosticinstrument, said instrument including a power supply, electricallyconfigured for powering an incandescent bulb as an illumination source,said instrument including an instrument head, a hand-grippable handleand at least one LED disposed in said instrument as the illuminationsource of said instrument, said adapter including means for electricallyinterconnecting said power supply and said at least one LED foreffectively energizing said at least one LED.

[0015] According to still another preferred aspect of the presentinvention, there is provided a method for adapting a medical diagnosticinstrument for use with at least one LED as an illumination source, saidinstrument including a power supply typically only electricallyconfigured for energizing an incandescent lamp as an illuminationsource, said method comprising the steps of:

[0016] adding an adapter to at least one of said instrument head, saidinstrument handle, and said instrument power supply; and electricallyconnecting said adapter to said power supply and to said at least oneLED to energize same without modification to said power supply.

[0017] According to yet another preferred aspect of the invention, thereis provided a method for adapting a existing medical diagnosticinstrument so as to incorporate at least one LED as an illuminationsource, said existing instrument including a power supply for energizinga miniature incandescent bulb as an illumination source, said instrumentincluding an existing instrument head and a existing instrument handlewherein said existing instrument head and said existing instrumenthandle include mating interconnecting ends which interlock saidinstrument head and said handle in a mechanical interconnection whilesimultaneously maintaining an electrical interface between saidincandescent lamp and said power supply, said method including the stepsof:

[0018] attaching an adapter between said instrument head and saidinstrument handle, said adapter including means for electricallyinterconnecting at least one LED and said power supply as well as meansfor mechanically interconnecting said instrument head and saidinstrument handle; and

[0019] mounting said at least one LED in one of said adapter and saidinstrument head.

[0020] An advantage of the present invention is that the hereindescribed electrical adapter permits a number of hand-held medicaldiagnostic instruments to be used with any previously existing powersupplies or battery charging apparatus used therein without significantmodification.

[0021] Still another advantage of the present invention is that theherein described electrical adapter permits each of the advantages ofLEDs to be brought to the diagnostic instrument. These advantages whichinclude longer lamp life, longer battery life, reduced maintenance, andhigher reliability without significantly impacting cost which heretoforecould not easily be brought to the instrument without significantredesign of the electrical system.

[0022] These and other objects, features, and advantages will becomereadily apparent from the following Detailed Description which should beread in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023]FIG. 1 is a partial side section view of the head of a prior artmedical diagnostic instrument;

[0024]FIG. 2 is a partial side sectioned view of the medical diagnosticinstrument of FIG. 1, including a portable battery power source;

[0025]FIG. 3 is a front view of another prior art medical instrumentincluding a wall-mounted power supply;

[0026]FIG. 4 is a side perspective view of a prior art diagnosticinstrument illustrating the interconnection between an instrument headand the instrument handle/power supply;

[0027]FIG. 5 is an enlarged side perspective view of the instrumenthead/handle-power supply interconnection of FIG. 4;

[0028]FIG. 6 is a partial side view of the interconnection betweenanother prior art instrument head and instrument handle;

[0029]FIG. 7 is an unassembled view of the instrument of FIG. 6;

[0030]FIG. 8 is a schematic block diagram of an LED electrical adaptermade in accordance with the present invention;

[0031]FIG. 9 is an electrical circuit diagram of an embodiment of theLED electrical adapter of FIG. 8;

[0032]FIG. 10 is an electrical circuit diagram of a current compensationportion of the LED electrical adapter of FIG. 8;

[0033]FIG. 11 is a side elevational view, partially in section, of amedical diagnostic instrument having an LED electrical adapter made inaccordance with a preferred embodiment of the present invention;

[0034]FIG. 12 is a side elevational view, partially in section, of amedical diagnostic instrument having an LED electrical adapter made inaccordance with another preferred embodiment of the present invention;

[0035] FIGS. 12(a) and 12(b) are side elevational views of a diagnosticinstrument head, partially in section, including means for detecting theillumination mode of the head in accordance with a preferred embodimentof the present invention;

[0036]FIG. 13 is a side elevational partial perspective view of a LEDelectrical adapter for a medical diagnostic instrument made inaccordance with yet another preferred embodiment of the presentinvention;

[0037]FIG. 14 is a side perspective view of the LED electrical adapterof FIG. 13;

[0038]FIG. 15 is a side elevational view of a portion of the adapter ofFIGS. 13 and 14; and

[0039]FIG. 16 is a circuit diagram of a microcontroller system fordetecting the presence of an incandescent bulb or an LED.

DETAILED DESCRIPTION

[0040] The following description relates in general to an LED electricaladapter that can be used in a hand-held medical diagnostic instrument,such as an ophthalmoscope, otoscope, vaginoscope, and the like, thoughthe embodiments described herein detail a specific instrument, namely anotoscope.

[0041] Prior to discussing the invention and referring to FIGS. 1 and 2,there is first shown a medical hand-held diagnostic instrument that isalready known in accordance with the prior art. In this instance, thediagnostic instrument 10 is a conventional otoscope, used for theexamination of the outer ear, including the tympanic membrane. Thisinstrument 10 generally includes a hollow instrument handle 14 and aninstrument head 18 that is attached to the top of the handle. Theinstrument head 18 is hollow and includes a frusto-conical tip portion40 onto which a disposable speculum (not shown) is fitted in aconventional manner, such as a bayonet 44. The speculum is sized forfitting a predetermined distance into the ear canal of a patient, thetip portion 40 having a distal tip opening 42. An eyepiece 46 attachedto the proximal end 48 of the instrument head 18 forms an optical pathwith the distal tip opening 42 through the hollow instrument head 18 topermit viewing of the medical target.

[0042] A miniature incandescent lamp 22, such as a halogen or xenonlamp, is provided in a lamp housing 25 that is disposed in a base 27 ofthe instrument head 18, the lamp being electrically connected through acontact 29 and a vertically extending pin 31 to a series of stackedNickel cadmium batteries 26 that are retained in a bottom compartment ofthe instrument handle 14 for energizing the lamp 22. The instrumenthandle 14 also contains a bottom or lower contact spring 33. Anadjustable voltage control 30 located on the exterior of the upperportion of the instrument handle 14 selectively adjusts the amount ofillumination output provided by the miniature lamp 22.

[0043] In addition to the above and referring to FIGS. 4-7, an effectivemechanical interface is essential in order to maintain electricalcontact between a miniature incandescent lamp contained in the head inthe manner detailed above and the contained power supply. A pair ofprior art instruments 10A, 10B therefore each include a mechanicalinterface between the instrument head 18A, 18B and the upper end of theinstrument handle 14A, 14B such that when the instrument head isattached to the handle that the above electrical connection ismaintained between the lamp and the power supply for the instrument.

[0044] In the prior art examples illustrated in FIGS. 4-7, each of theinstruments employ a form of a bayonet connection. In the instrumentaccording to FIGS. 4 and 5, the base 27A of the instrument head 18Aincludes an interior set of slots (not shown) for engaging acircumferential set of ears 32 (only one being shown) provided on theexterior of the upper portion 28A of the handle 14A. A functionallysimilar instrument is shown in FIGS. 6 and 7 for an ophthalmoscope inwhich the base 27B includes a set of ears 37 for engaging acorresponding set of slots located in the upper portion 28B of theinstrument handle 14B to permit the electrical contact 39 to be placedinto electrical contact with the power supply of the instrument topermit illumination of the lamp disposed within the base 27B. Othersuitably similar interfaces can be utilized as these depicted areintended only to be exemplary. In addition, it is known that bymaintaining these mechanical and electrical interfaces/connections thatvarious instrument heads and/or handles, including those from differentmanufacturers, can be combined in a single hand-held instrument.

[0045] Alternately and in lieu of batteries, a hand-held medicaldiagnostic instrument handle 50 can be tethered by means of a cord 52directly to a wall transformer or similar power supply 54, such as shownin FIG. 3. In each particular instance and referring to FIG. 1, a seriesof optical fibers 38 extend from the miniature incandescent lamp 22through the base 27 of the instrument head 18, to a bundle of lighttransmitting ends 36 or other optical means that are disposed at thedistal tip opening 42 in order to provide illumination of the medicaltarget (e.g., the tympanic membrane). One typical wall transformer isfurther described in U.S. Pat. No. 5,559,422, incorporated herein in itsentirety.

[0046] With the preceding background and referring now to FIG. 8, thereis shown a block diagram of an LED electrical adapter 60 made inaccordance with a preferred embodiment of the present invention. Thiselectrical adapter 60 includes a number of primary features that arerequired in order to permit already existing power supplies, such asthose shown in FIGS. 1-7, to be used in conjunction with at least onewhite LED package 64 that would be substituted for the miniatureincandescent lamp 22, FIG. 1, in a medical diagnostic instrument.

[0047] As will be apparent from the following discussion, the mechanicaland electrical design of the inventive adapter can assume a plurality ofelectrical, mechanical and electrical configurations covered in generalby all or some features of the block diagram of FIG. 8, permitting theadapter to be used in conjunction with literally any existing powersupply that provides power to an incandescent lamp-equipped medicaldiagnostic instrument.

[0048] In general, the LED electrical adapter 60 includes a voltageconversion portion 84 and a compensation portion 100. Each of thesefeatures will now be described in greater detail. It should be notedthat for illustration purposes that the compensation portion is presumedto be a current compensation portion, although other characteristicssuch as voltage, light output and/or color compensation are similarlyimplemented.

[0049] First, the voltage conversion portion 84 herein is an AC or DCconverter which can be constructed, for example, as a simple diodebridge so as to provide proper selection of the forward voltage drop ofat least one white LED package 64. Alternately, there are a number ofso-called “no drop” MOSFET switches, such as those manufactured byVishay-Siliconix, among others, could preferably facilitate the voltageconversion with minimal loss in power. Provision of this conversionportion 84 permits both AC and DC power supplies to utilized. Inaddition, any polarity mismatch between the LED package 64 and thepreviously utilized miniature incandescent lamp 22 would also becorrected using this converter portion.

[0050] That is to say, while miniature incandescent lamps are unaffectedby opposite polarity from a power source. LEDs require unipolar DCcurrent in order to illuminate.

[0051] The current compensation portion 100 can include each of thefollowing: a general current compensation means 104 for provided alimited maximum current, and a high/low stopper regulator 108.

[0052] As far as simple current compensation is concerned, a resistor ora PTC (positive thermal coefficient e.g., thermistor) can be used,though it is believed this is not the optimal solution. There are tworeasons for this belief. First, there are variabilities between LEDs interms of output versus current. Therefore, this “solution” providespartial compensation to an “average” white LED in average conditions.Additionally, this form of current compensation may not adequatelycompensate under low and high supply voltage conditions because theresulting differential voltage between the power source and the LEDforward voltage will be directly translated into current difference whenusing a PTC or resistor as the compensating element. In some instances,the LED forward voltage will be higher than the source voltage andtherefore no conduction will occur at all. For instance, a typical 3.5volt battery power handle ranges between 3.0 volts and 4.2 volts and atypical white LED (such as, for example, a Lumileds Luxeon LXHL-MWIA)has a forward voltage of between about 2.55 volts and about 3.99 volts.These low voltage conditions would occur as the batteries within theinstrument handle discharge, or with low line or power supplies that areset at the low end of their manufacturing tolerances.

[0053] In addition, high voltage conditions could conversely causeexcessive current to flow, resulting in very poor color or in theextreme, failure of the device itself. These high voltage conditionswould occur with new, fully charged batteries, or at high line of powersupplies set at the high end of manufacturing tolerances.

[0054] Regulating/limiting systems for current compensation can includefor example, linear regulators, such as, for example, a NationalSemiconductor LM1117. Alternately, a bimetallic switch can be appliedwhich can be set to create a duty cycle which averages a correctedcurrent in order to produce a stable consistent output as long as thevoltage provided by the power source is sufficiently above the forwardvoltage of the LED.

[0055] Referring to FIG. 9, a circuit is herein described that controlsthe voltage to an LED which is used in lieu of a miniature incandescentbulb. As will be noted below and with relatively small modification, thecircuit can further be configured to control the light output of the LEDor the color output of the LED by selecting the appropriate detector(photodiode with or without filter) and connecting the detector to thesense feed line. The voltage control circuit of FIG. 9 functions asfollows:

[0056] An oscillator (U1) is assumed to be a voltage controlledoscillator having a base frequency and a duty cycle that is a functionof the input voltage. There are many PWM (pulse width modulation) typedevices available, and this circuit does not rely on any particular suchdevice. Upon initial power up of the circuit, the voltage across a pairof resistors (R2) and (R3) would be zero, and the sense voltage would bezero. Once a comparator (U2) powers up, the sense voltage (zero atstart) will be compared with the reference (U3) and a positive errorsignal will be generated. This error is fed to the oscillator (U1) whichincreases its on time cycle, thereby driving transistor (Q1) to turn on.The preceding causes current to flow through an inductor (L1) and storesenergy as an electromagnetic field. During the “off” cycle of theoscillator (Q1) turns off and all current is then fed forward into adiode (D1). This feeding creates a voltage and drives current into theLED when the voltage becomes higher than the LED threshold (forwardvoltage) which is sensed via a pair of voltage dividers (R2) and (R3).If this voltage remains lower than the reference (U3), the errorcomparator (U2) continues to generate a positive error and theoscillator continues to increase its pulse width which increases theenergy which is stored in (L1), and consequently the output voltage intothe LED. When the output and therefore the sense voltage becomes higherthan that of the reference (U3), the error comparator (U2) generating anegative error signal which decreases the oscillator on time to reducethe output voltage. This process continues and maintains the outputclose to the reference voltage that is selected. The reference voltageis chosen to be the optimum setting for LED operation.

[0057] While the above is a basis version, it should be noted that byincluding a resistor in series with the load, as shown in FIG. 10,rather than in parallel, this circuit represents a simplified currentcontrol, as represented in compensation block 100, FIG. 8. In addition,any other sensing means can be introduced such that the above circuitwould respond to other changes such as light level, color, etc.

[0058]FIG. 9 includes a means for adequate energy storage in L1, FIG. 9,to bring the apparent source voltage to the LED above the forwardvoltage of the LED and then regulate the subsequent current which isdrawn. Alternately, the regulator can be replaced by a low resistanceMOSFET.

[0059] Including an oscillator to the design of the current compensationportion as in FIG. 9 would also permit dimming of the LED using either aduty cycle or a pulse width modulation technique. Since LEDs do not dimgradually and predictably with a decrease in voltage, use of the dutycycle would take advantage of the LEDs relatively fast “on/off” time tocreate “apparent” dimming for the user.

[0060] In addition, color will change as current is changed. Therefore,directly decreasing current to adjust light output, for example, willproduce an undesirable variation in color. By utilizing either a dutycycle or pulse width modulation as a dimming “technique” for the LED,the LED is pulsed at virtually full power, but for shorter periods oftime and therefore appears to dim. The current remains at the “normal”full on value during these pulses, therefore the color of the LED doesnot perceivably change as the LED is dimmed.

[0061] Depending on the degree of complexity and/or cost considerations,the oscillator can be replaced with a bimetallic element. Thissubstitution also provides the opportunity to modify the light output byrapidly pulsing the LED at a duty cycle which represents the modifiedintensity desired.

[0062] Having described the basic circuitry and referring now to FIGS.11-15, a number of potential locations for the herein describedelectrical LED adapter can be assumed, exemplary embodiments beingherein described. For example and first referring to FIG. 11, there isillustrated a battery-powered diagnostic instrument 120, such aspreviously described in FIGS. 1 and 2, that further includes an adaptormodule 124 carrying the electrical circuitry of FIGS. 9 and/or 10, themodule being disposed between the instrument head 128 and the top of thehandle 132. The adapter 124 includes a housing 136 including a residentprinted circuit board 140 and respective electrical contacts 144, 148provided at opposing ends of the housing. A white LED 152 such asdescribed in U.S. Pat. No. 5,998,925, previously incorporated above, isdisposed within a cavity 156 formed within the lower portion of theinstrument head 128 wherein the LED includes at least one contact 160that is placed in proximity with the upper facing contact 144 of theadapter 124. The lower facing contact 148 of the adapter 124 is arrangedin relation to the retained batteries 168 disposed within the handle132. A set of optics 172 are optionally disposed in relation to the LEDdie for coupling with the illumination output of the LED 152.

[0063] Referring to FIG. 12, a similarly designed LED electrical adapter176 can assume other locations relative to the medical diagnosticinstrument. The adapter 176, according to this embodiment, is disposedwithin a cavity 180 formed within the interior of the instrument head177 along with an LED 188 having contacts that engage a printed circuitboard 190 having the circuitry previously described. The adapter 176further includes a lower contact 194 that engages the batteries (notshown) provided in the handle (not shown).

[0064] Referring to FIGS. 13-15, another embodiment of an LED electricaladapter is provided that includes a compact cartridge 200 that is sizedso as to replace an existing battery typically retained within aninstrument handle 204. The adapter cartridge 200 is preferably definedin a cylindrical shape and is sized similarly to that of a containedbattery to permit fitting into the instrument handle 204 in lieuthereof. This electrical cartridge includes a slot 208 that retainsspecific voltage conversion means in the form of a voltage conversionmeans 220, having elements as defined above, the cartridge beingdisposed between one of the batteries 210 and the extending pin contactextending from the instrument head (not shown) as well as an extendingnegative contact strip 214 enabling a suitable electrical connectionbetween the battery 210 and the LED (not shown). Each of the aboveassemblies can be retained in a housing (not shown for clarity) ofconvenient size.

[0065] In addition to and in complement of the herein describedelectrical adapter, an optical system can be added or modified toimprove color. For example, a suitable filter and a collection lens canbe placed at the light transmitting end of an LED having its top lensremoved. The filter may also be part of this lens and the assembly mayalternately be part of the LED or incorporated into part of theinstrument head.

[0066] In addition to and in complement of the herein describedelectrical adapter, a means for detecting and switching the driveelectronics from an LED version to an incandescent lamp version of adiagnostic instrument is beneficial, since this switching ability allowsthe same instrument to take advantage of each illumination system. Thereare several means for accomplishing this goal. The most basic techniqueis the incorporation of a mode switch which is manually actuated by theuser of the instrument. This mode switch would connect the illuminationto either the incandescent lamp drive circuitry or the LED drivecircuitry based on the user's discretion.

[0067] The operation of an exemplary switch configuration is depicted inFIGS. 12(a) and 12(b) showing alternative illumination sources aspreviously described. In FIG. 12(a), an incandescent lamp 228 isdisposed in a diagnostic instrument head 232, such as an otoscope head,the incandescent lamp having leads 236, 240 extending to respectivecontact surfaces 244, 248. Contact surface 244 is located at the bottomof the lamp module 252 in a proximal end of the instrument head whilecontact surface 248 is located adjacent the lamp module 252. A thirdcontact surface 256 is established along the exterior of the instrumenthead 232, this portion of the head being separated from contact surface244 by an insulator 260.

[0068] The operation of the mode switch is based upon the combination ofcontact surfaces engaged. According to this embodiment, the incandescentlamp 228 is energized by supplying electrical energy from the handle orotherwise between contact surfaces 256 and 244, each of which are indirect contact with the lamp module 252.

[0069] In the embodiment of FIG. 12(b), on the other hand, an LED module266 is situated in the instrument head 232 wherein the LED 270 isenergized by supplying electrical energy between contact surfaces 244and 248, each of which are in direct electrical contact with the LEDmodule through respective electrical contacts 274 and 278 via electricaladapter 60.

[0070] As described, the adapter can provide a means for differentcontacts for the LED and the incandescent lamp, such that simplyinserting the desired illumination device automatically selects theproper drive circuitry/configuration. In yet another alternative of theinvention, the mechanical contact geometry can be the same for bothillumination devices, and the adapter electronics can detect thepresence or lack of polarity whether the illumination is an LED(polarized) or an incandescent bulb (not polarized). The above objectivecan be accomplished, in a preferred embodiment, using a microcontrollersystem such as illustrated in FIG. 16.

[0071] Referring to FIG. 16, a microcontroller U1 turns on halfH-bridges Q1/2 and Q3/4 sequentially and checks the resulting voltage atresistors R1 and R2. If the resulting voltage is the same, this providesan indicator that the current flow is symmetric in both directions,indicating a non-polarized illumination device and therefore the devicelocated at U4 in this circuit would be determined to be an incandescentlamp. If the voltage is different between R1 and R2, the device would bedetermined to be polarized, indicating that the device located at U4 isan LED. In addition, the direction of polarity would also be knownallowing the drive circuitry to be properly connected. One furtherbenefit of the above detection scheme is that it would also allowdetection of blown lamps or LED's if the current flow in each directiontested was found to be essentially zero. It is also noted thatmicrocontroller U1 is presumed to include an analog to digital converterthat is used to convert the analog voltage present at R1 and R2 to adigital reading. While there are several microcontrollers which havethis feature, the analog to digital converter could be implementedseparately if needed. Also, the drive circuitry and connection to U4 isintentionally left out of this diagram for the sake of simplicity and toconvey the essential concepts of the invention. However it should beobvious to one of sufficient skill in the field that it can beaccomplished even as simply as adding additional H-bridge sections (notshown) under microcontroller control.

[0072] Parts List for FIGS. 1-8 15]16

[0073]10 medical diagnostic instrument

[0074]10A, 10B diagnostic instrument

[0075]14 instrument handle

[0076]14A, 14B instrument handle

[0077]18 instrument head

[0078]18A, 18B instrument head

[0079]22 miniature halogen lamp

[0080]25 lamp housing

[0081]26 batteries

[0082]27 base

[0083]27A, 27B base

[0084]28A, 28B upper end

[0085]29 contact

[0086]30 adjustable voltage control

[0087]31 pin

[0088]32 ears

[0089]33 contact spring

[0090]36 light transmitting ends

[0091]37 ears

[0092]38 optical fibers

[0093]39 contact pin

[0094]40 tip portion

[0095]42 distal tip opening

[0096]44 bayonet

[0097]46 eyepiece

[0098]48 proximal end

[0099]50 instrument handle

[0100]52 cord

[0101]54 wall transformer

[0102]60 electrical LED adapter

[0103]64 LED package

[0104]84 AC or DC converter

[0105]100 current compensation portion

[0106]120 instrument

[0107]124 adaptor module

[0108]128 instrument head

[0109]132 handle

[0110]136 housing

[0111]140 printed circuit board

[0112]144 contact

[0113]148 contact

[0114]152 LED

[0115]156 cavity

[0116]160 contact

[0117]168 batteries

[0118]172 optics

[0119]176 adapter

[0120]177 instrument head

[0121]180 cavity

[0122]188 LED

[0123]190 printed circuit board

[0124]194 lower contact

[0125]200 cartridge

[0126]204 handle

[0127]208 slot

[0128]210 batteries

[0129]214 negative contact strip

[0130]220 voltage conversion means

[0131]228 incandescent lamp

[0132]232 instrument head

[0133]236 lead

[0134]240 lead

[0135]244 contact surface

[0136]248 contact surface

[0137]252 lamp module

[0138]256 contact surface

[0139]260 insulator

[0140]266 LED module

[0141]270 LED

[0142]274 electrical contact

[0143]278 electrical contact

[0144] Though the following description has been made in terms ofcertain embodiments, it will be readily apparent that othermodifications and variations are possible which encompass the spirit andscope of the herein claimed invention.

We claim:
 1. An adapter for use with a medical diagnostic instrumenttypically configured with an incandescent lamp as an illumination sourceand a power supply for powering said incandescent lamp, said adapterhaving means for permitting at least one LED to be used as theillumination source for said instrument while permitting said existingpower supply to used therewith.
 2. An adapter as recited in claim 1,wherein said at least one LED is a white LED.
 3. An adapter as recitedin claim 1, including means for limiting the current supplied to said atleast one LED by said existing power supply.
 4. An adapter as recited inclaim 3, including means for boosting the voltage supplied to said atleast one LED by said existing power supply.
 5. An adapter as recited inclaim 1, including means for compensating the current drawn by said atleast one LED from said existing power supply.
 6. An adapter as recitedin claim 5, including means for boosting the voltage supplied to said atleast one LED by said existing power supply.
 7. An adapter as recited inclaim 1, including means for matching the polarity between said at leastone LED and said existing power supply.
 8. An adapter as recited inclaim 7, including means for limiting the current to said at least oneLED from said existing power supply.
 9. An adapter as recited in claim7, including means for compensating the current drawn by said at leastone LED from said existing power supply.
 10. An adapter as recited inclaim 8, including means for boosting the voltage supplied to said atleast one LED from the existing power supply.
 11. An adapter as recitedin claim 9, including means for boosting the voltage supplied to said atleast one LED from the existing power supply.
 12. An adapter as recitedin claim 1, including means for compensating the voltage supplied tosaid at least one LED from said existing power supply.
 13. An adapter asrecited in claim 12, wherein said voltage compensating means includesmeans for boosting the voltage supplied to said at least one LED.
 14. Anadapter as recited in claim 1, including means for compensating thelight output of said at least one LED.
 15. An adapter as recited inclaim 14, wherein said light output compensating means includes meansfor boosting the voltage supplied to said at least one LED.
 16. Anadapter as recited in claim 14, including means for dimming said atleast one LED.
 17. An adapter as recited in claim 1, including means forcompensating the color sense of said at least one LED.
 18. An adapter asrecited in claim 17, including wherein said color compensating meansincludes means for boosting the voltage of said at least one LED.
 19. Anadapter as recited in claim 17, including at least one optical filter.20. An adapter as recited in claim 1, wherein said adapter includes saidat least one LED.
 21. An adapter as recited in claim 1, including atleast one optical element disposed in relation to said at least one LEDused as the illumination source.
 22. An adapter as recited in claim 21,including at least one optical filter disposed in relation to said atleast one optical element.
 23. In combination, an adapter for use with amedical diagnostic instrument, said instrument including a power supply,electrically configured for powering an incandescent bulb as anillumination source, said instrument including an instrument head, ahand-grippable handle and at least one LED disposed in said instrumentas the illumination source of said instrument, said adapter includingmeans for electrically interconnecting said power supply and said atleast one LED for effectively energizing said at least one LED.
 24. Acombination as recited in claim 23, wherein said adapter isindependently attached between said instrument head and said handle. 25.A combination as recited in claim 23, wherein said at least one LED ispart of an LED module.
 26. A combination as recited in claim 25, whereinsaid adapter is disposed in said LED module.
 27. A combination asrecited in claim 25, wherein said module includes at least one opticalelement disposed in relation to the output of said LED.
 28. Acombination as recited in claim 23, wherein said adapter is disposed insaid instrument head.
 29. A combination as recited in claim 23, whereinsaid adapter is disposed in the hand-grippable handle.
 30. A combinationas recited in claim 23, wherein said adapter is disposed in the powersupply of said instrument.
 31. A combination as recited in claim 23,wherein said adapter permits said at least one LED to be energized bysaid power supply without modification thereof.
 32. A combination asrecited in claim 31, wherein said instrument includes at least one of atleast one LED and an incandescent lamp as the illumination source forsaid instrument, said combination further including means forselectively activating said adapter depending on the illumination sourceprovided in said instrument.
 33. A combination as recited in claim 32,including means for sensing the type of illumination source in saidinstrument.
 34. A combination as recited in claim 32, including modeswitching means connected to said adapter for enabling said adapter ifat least one LED is used as the instrument illumination source.
 35. Acombination as recited in claim 33, wherein said illumination sensingmeans includes means for sensing whether there is a polarity differencebetween said power supply and the illumination source and means forautomatically enabling said adapter if there is a sensed polaritydifference.
 36. A combination as recited in claim 29, wherein saidhandle is modified to permit use of said at least one LED.
 37. Acombination as recited in claim 30, wherein said power supply ismodified to permit use of said at least one LED.
 38. A combination asrecited in claim 24, wherein said instrument head and saidhand-grippable handle include interconnect means for interconnectingsaid head to said handle for providing a mechanical interface andmaintaining an electrical interface between said power supply and anincandescent lamp when an incandescent lamp is typically used in theinstrument, and in which said adapter includes respective ends adaptedto connect to said interconnect means to provide said mechanicalinterface while creating an electrical interface between said powersupply and said at least one LED.
 39. A combination as recited in claim38, wherein said at least one LED is disposed in an LED module.
 40. Acombination as recited in claim 39, wherein said LED module is disposedin said instrument head.
 41. A combination as recited in claim 39,wherein said LED module is disposed in said adapter.
 42. A combinationas recited in claim 23, wherein said at least one LED is disposed in theinstrument head.
 43. A combination as recited in claim 23, wherein saidat least one LED is disposed in the adapter.
 44. A combination asrecited in claim 23, wherein said at least one LED is a white LED.
 45. Amethod for adapting a medical diagnostic instrument for use with atleast one LED as an illumination source, said instrument including apower supply typically only electrically configured for energizing anincandescent lamp as an illumination source, said method comprising thesteps of: adding an adapter to at least one of said instrument head,said instrument handle and said instrument power supply and electricallyconnecting said adapter to said power supply and said at least one LEDto energize same without modification to said power supply.
 46. A methodas recited in claim 45, including the step of limiting the currentsupplied to said at least one LED by said power supply.
 47. A method asrecited in claim 45, including the step of adjusting the voltagesupplied to said at least one LED by said power supply.
 48. A method asrecited in claim 45, including the step of compensating the currentdrawn by said at least one LED from said power supply.
 49. A method asrecited in claim 48, including the step of boosting the voltage suppliedto said at least one LED by said power supply.
 50. A method as recitedin claim 45, including the step of matching the polarity between said atleast one LED and said power supply.
 51. A method as recited in claim50, including the step of limiting the current to said at least one LEDfrom said power supply.
 52. A method as recited in claim 50, includingthe step of compensating the current drawn by said at least one LED fromsaid power supply.
 53. A method as recited in claim 51, including thestep of boosting the voltage supplied to said at least one LED from thepower supply.
 54. A method as recited in claim 52, including the step ofboosting the voltage supplied to said at least one LED from the powersupply.
 55. A method as recited in claim 45, including the step ofcompensating the voltage supplied to said at least one LED from saidpower supply.
 56. A method as recited in claim 55, wherein said voltagecompensating step includes the step of boosting the voltage supplied tosaid at least one LED.
 57. A method as recited in claim 45, includingthe step of compensating the light output of said at least one LED. 58.A method as recited in claim 57, wherein said light output compensatingstep includes the step of boosting the voltage supplied to said at leastone LED.
 59. A method as recited in claim 57, including the step ofdimming said at least one LED.
 60. A method as recited in claim 45,including the step of compensating the color sense of said at least oneLED.
 61. A method as recited in claim 60, wherein said colorcompensating step includes the step of boosting the voltage of said atleast one LED.
 62. A method as recited in claim 60, including the stepof optically filtering said at least one LED.
 63. A method as recited inclaim 45, including the step of disposing said at least one LED intosaid adapter.
 64. A method as recited in claim 45, including the step ofcoupling at least one optical element in relation to the output of saidat least one LED.
 65. A method as recited in claim 64, including thestep of placing at least one optical filter in relation to said at leastone optical element.
 66. A method as recited in claim 45, including thestep of independently attaching an adapter between said instrument headand said handle.
 67. A method as recited in claim 66, wherein said atleast one LED is part of an LED module and in which said method includesthe step of disposing said adapter in said LED module.
 68. A method asrecited in claim 45, wherein said instrument includes at least one of atleast one LED and an incandescent lamp as the illumination source forsaid instrument, method including the additional step of selectivelyactivating said adapter depending on the illumination source provided insaid instrument.
 69. A method as recited in claim 68, including the stepof sensing the illumination source in said instrument.
 70. A method asrecited in claim 69, wherein said illumination sensing step includes theadditional steps of determining if there is a polarity differencebetween said power supply and the illumination source and automaticallyenabling said adapter if there is a sensed polarity difference.
 71. Amethod as recited in claim 66, including the step of providing amechanical interface between said instrument head and said instrumenthandle that maintains an electrical interface between said power supplyand said at least one LED, said at least one LED being located in one ofthe instrument head and the adapter.
 72. A method for adapting aexisting medical diagnostic instrument so as to incorporate at least onewhite LED as an illumination source, said existing instrument includinga power supply for energizing a miniature incandescent bulb as anillumination source, said instrument including an existing instrumenthead and a existing instrument handle wherein said existing instrumenthead and said existing instrument handle include mating interconnectingends which interlock said instrument head and said handle in amechanical interconnection while simultaneously maintaining anelectrical interface between said incandescent lamp and said powersupply, said method including the steps of: attaching an adapter betweensaid instrument head and said instrument handle, said adapter includingmeans for electrically interconnecting at least one LED and said powersupply as well as means for mechanically interconnecting said instrumenthead and said instrument handle; and mounting said at least one LED inone of said adapter and said instrument head.
 73. A method as recited inclaim 72, including the step of attaching a new instrument head havingsaid at least one LED to said adapter.
 74. A method as recited in claim72, including the steps of removing said incandescent bulb from saidinstrument head and mounting said existing instrument head onto saidadapter, wherein said at least one LED is disposed in said adapter.